Rocking device

ABSTRACT

A rocking device is described for receiving a lower part of a carriage, perambulator, cot or the like in particular to rock an infant therein, with oscillation means to impart an oscillating motion thereto comprising an elongate roller ( 2 ) mounted about a generally longitudinal axis, and drive means ( 9 ) associated therewith to cause the roller to rotate, the transverse shape of the roller and the position of the axis together being such that the roller imparts an oscillating motion to the carriage in mechanical engagement therewith in use. A method of rocking a carriage, perambulator, cot or the like is also described.

[0001] The invention relates to a device and method for imparting anoscillating or rocking motion to a carriage, perambulator, cot bed orthe like, in particular for soothing a baby or infant therein.

[0002] It is well known that distressed and crying babies in a carriage,pram, cot or the like can be soothed by rocking. This is particularly sowhen the baby is in a wheeled carriage, which facilitates theapplication of a continuous rocking motion for a period of time tosoothe the baby.

[0003] Conventionally, the rocking action is applied directly to thebaby's carriage by the baby's parent or other carer. However, thisprocedure, although effective, is time consuming, physically demanding,and likely to be frustrating particularly having regard to the alreadyfrustrated state of mind which the carer may find triggered by thebaby's continuous crying. The development of a mechanical device whichthe carer could therefore use to impart this rocking motion wouldclearly be beneficial.

[0004] Whilst a number of devices exist in more developed technicalfields to impart oscillating motion to bodies contained therein, it isan overriding consideration for devices for use by the parents or othercarers of babies and young children that the devices should be ofsuitable scale, robust, and mechanically simple (both for ease ofoperation and to keep costs reasonable). In consequence, many knownoscillating devices are likely to be unsuitable for this application.

[0005] A number of mechanical devices exist which impart horizontal,reciprocating oscillation to a baby carriage (for example UK PatentApplication 2061836, 2191448 and 2145981). However, these fail to takeadvantage of the known soothing effect which can be attributed to atleast some degree of vertical rocking motion.

[0006] An attempt to provide a device for importing a rocking motionincluding an up-and-down element to a baby carriage is described in U.S.Pat. No. 5,002, 144. In this device a drive motor drives torqueconverters which act on lifting cams to cause up and down motion ofpistons, the pistons acting on a wheel receiving plate to produce arocking motion on the pram wheels. Although this device produces an upand down motion, it is of considerable mechanical complexity, and istherefore inherently likely to be less robust and more expensive thanwould a simpler design.

[0007] Moreover, U.S. Pat. No. 5,002,144 concentrates on up and downmotion only, whereas in practice a combination of up and down andreciprocating motion, and in particular an orbital oscillation motion,has been shown to be effective. Attempts have been made to adaptedreciprocating drive systems for use in conjunction with ramps (see forexample UK patent 2 150 086) to give motion in both a vertical andhorizontal sense, but these are cumbersome, and motion is stillessentially linear rather than orbital.

[0008] It is an object of the present invention to provide a baby rockerand associated rocking method which mitigate some or all of the abovedisadvantages, and in particular to provide a baby rocker and methodwhich is capable of imparting at least some vertical oscillation whilstat the same time remaining relatively mechanically simple. It is aparticular object of the present invention to provide a baby rocker andassociated rocking method which is capable of imparting at least someoscillation both in a vertical and horizontal sense, and in particularan orbital motion.

[0009] According to a first aspect of the invention, a rocking device inits broadest embodiment comprises means for receiving a lower part of acarriage, perambulator, cot bed or the like, an oscillation means forimparting an oscillating motion thereto comprising an elongate rollermounted about a generally longitudinal axis, and drive means associatedtherewith to cause the roller to rotate, the transverse shape of theroller and the position of the axis together being such that the rollerimparts an orbital oscillating motion to the carriage in mechanicalengagement therewith in use.

[0010] The elongate roller is disposed generally horizontally, and ismounted about a generally horizontal axis. The transverse profile of theroller surface and the axis together ensure that as the roller rotates,the position of the point of the roller's surface acting on the carriagein mechanical engagement therewith oscillates orbitally (i.e. bothupwards and downwards and laterally). This is achievable primarily inthat in the roller is mounted about an eccentric axis. The roller mayhave a generally circular-cylindrical shape, and such a constructionwill be preferred in many instances for simplicity. Alternatively, theorbital motion may be modified in that the roller itself may beeccentrically shaped (i.e. non-circular) in transverse section. Forexample, the roller may be of elliptical section.

[0011] The lower part of the carriage is so located as to be inmechanical association with the roller. The roller may thus be used tobe impart such orbital oscillating motion to the baby carriage,perambulator, cot or the like. The motion is applied by the rollereither by acting directly on a lower portion of the carriage (the rollerthen comprising part of the receiving means) or by acting on anengagement surface of a separate receiving means to impart orbitaloscillating motion thereto which receiving means transmits motion to acarriage received thereon.

[0012] Thus, the device in accordance with the invention is capable ofimparting an orbital oscillation to a baby carriage or cot in a devicewhilst remaining of great mechanical simplicity when compared with priorart devices having the same capability. In particular, it can be notedthat at its simplest a single moving part is sufficient to convert thedrive from the drive means to orbital motion of the carriage.

[0013] The geometry of the roller and of its mounting are such that ifthe carriage is mechanically engaged therewith in appropriateorientation, the carriage may be urged to oscillate in both a verticaland a horizontal sense, and in particular, if appropriately located, theroller will impart an orbital motion to the carriage in mechanicalengagement therewith.

[0014] Accordingly, the receiving means are preferably so configured asto locate the carriage in position in mechanical engagement with rollersuch that the roller impart an oscillating motion to the carriage havingboth a horizontal and a vertical component so that the roller imparts anorbital motion to the carriage.

[0015] The roller is mounted on a suitable housing, which is providedwith a lower surface adapted to engage the ground to maintain thestability of the device. As the roller rotates, the effect of eccentricmounting and optional eccentric transverse section is that the uppermostsurface of the roller presented to engage the carriage periodicallyvaries in position relative to the ground, imparting an orbital rockingmotion.

[0016] In accordance with the invention an eccentrically mounted rolleris used to impart an orbital motion to the carriage. In particular, theeccentrically mounted roller presents a generally cylindrical rollingsurface. In a simple embodiment the roller comprises a solid or hollowelongate cylinder having an offset axial mounting. However, it will beunderstood that the principles of the invention do not require thecylinder to be complete, and mounted about a physical axis, but extendto cover any mounted roller structures having one or more rollingsurfaces of generally circular or arcuate symmetry and mounted such asto impart an orbital motion about a real or virtual eccentric axis. Forexample, the roller may comprise an elongate central structural portion,offset mounted, and provided with one or more annular rolling surfaceportions whose radially external surfaces comprise the rolling surfacesin use. This might have advantages for example in terms of reducedweight, material selection, provision of bearings etc.

[0017] References herein to a baby carriage are to any object in which ababy or infant may be placed, whether a wheeled carriage or a static cotor the like. However, the invention is particularly applicable towheeled carriages such as perambulators, buggies, push-chairs andsimilar. For this application, the receiving means are preferablyadapted to receive the wheels of the wheeled carriage. Where the wheeledcarriage has more than one pair of wheels, the receiving means isconveniently adapted to receive just one such pair, in particular havinga common axle, the other pair(s) being able to rest upon the ground. Theaction of the roller on the receiving means thereby imparts an orbitalmotion to the carriage which the other wheels on the ground are able toaccommodate.

[0018] The invention is particularly suited to rocking a baby carriageor cot and examples are given in that context but it will be understoodthe same principle could be applied to rocking a bed for an infant oreven an adult.

[0019] In a preferred embodiment, particularly applicable to, though notlimited to, use with a wheeled carriage, the device comprises aplurality of rollers, and in particular a pair of generally parallelrollers. It is not necessary for all such rollers to be oscillators, andat least some of the rollers, and where a pair of rollers are providedone of the pair, may be centrally mounted and circular-cylindrical. Thisembodiment is particularly suited to wheeled carriages, with a pair ofrollers serving as a particularly stable means for receiving a wheel orwheels of the carriage, and in particular a single pair of wheels havinga common axle. Preferably, the oscillating roller is similarly generallycircular cylindrical, but mounted on an eccentric axis.

[0020] Such an arrangement is particularly effective in imparting anorbital motion including both horizontal and vertical components to thecarriage, since as the wheels engage between a pair of rollers, one ofwhich is configured to impart eccentric motion, an orbital oscillatingmotion will be inherently produced.

[0021] It will be appreciated that it is not necessary to associate thedrive means directly with both rollers of such a pair. Preferably, oneroller is driven and the other is freely rotating. In the embodimentwhere at least a pair of rollers comprises an oscillating roller such asan eccentrically mounted roller and a centrally mounted cylindricalroller, it will normally be preferable for the drive means to actdirectly upon the oscillating roller, but it will be appreciated thatthis is not a strict requirement, and that the centrally mounted rollercould be driven directly, transmitting rotational drive to theoscillating roller through the wheels for a wheeled carriage engagedthereon for example.

[0022] In an alternative embodiment a single oscillating roller may beprovided, adapted to act upon the receiving means, for example in theform of a mounting means mechanically engaged thereupon, to impart anorbital motion to a carriage or the like positioned upon the receivingmeans in use.

[0023] The roller or rollers may serve to comprise, at least in part,the means for receiving the lower part of the carriage. As indicated,such an arrangement is particularly effective for receiving the wheelsof a wheeled carriage, and in particular a single pair of wheels havinga common axle. Additionally or alternatively, a mounting plate may beprovided comprising a mounting portion which seats over at least theoscillating roller and a receiving portion for receiving the lower partof the said carriage. The receiving portion may seat and in usereciprocate over other non eccentric roller(s) where present.Alternatively, such other roller(s) may be dispensed with entirely or bereplaced or supplemented by bearings over which the receiving portionmay seat and in use reciprocate when driven by the eccentric roller.

[0024] The receiving portion may merely provide a base for the wheels orlegs of a carriage, or may incorporate or have provision for retainingmeans to stably retain the same.

[0025] In the case of the embodiment of the invention comprising aplurality of rollers, it will be appreciated that the mounting plate maycomprise further mounting portions to seat over some or all of thefurther rollers, and optionally further receiving portions as the casemay be. The mounting plate will in use reciprocate over the furtherrollers where present as it is driven by the eccentric oscillatingroller. Alternatively, such other rollers may be dispensed with entirelyor be replaced or supplemented by bearings over which the receivingportion may seat and in use reciprocate when driven by the eccentricoscillating roller.

[0026] In a preferred embodiment comprising an eccentrically mountedroller and a centrally mounted roller, both generallycircular-cylindrical, the mounting plate comprises a first mountingportion configured to engage the eccentrically mounted roller, a secondmounted portion configured to engage the centrally mounted roller, and areceiving portion therebetween. Conveniently, the mounting plate extendslaterally over a substantial part of the length of the rollers, andfurther preferably the receiving portion has a generally U-shapedtransverse section, the first mounting portion has a generally L-shapedsection extending laterally across and then projecting vertically downto engage the eccentric roller in use, and the second mounting portioncomprises a laterally extending lip to seat upon the centrally mountedroller in use. This arrangement provides maximum stability of engagementwith the eccentrically mounted roller, whilst allowing some lateralmovement of the plate in sliding engagement with the centrally mountedroller during use to improve stability.

[0027] In an alternative embodiment comprising a generallycircular-cylindrical eccentrically mounted roller only, within asuitable roller housing, the mounting plate comprises a first mountingportion configured to engage the eccentrically mounted roller, a secondmounted portion configured to engage a laterally spaced portion of theroller housing, in particular in pivoting and/or sliding engagement tofacilitate orbital motion of the mounting plate under impulse of theeccentrically mounted roller in use, and a receiving portiontherebetween. In the absence of the second roller, bearing surfaces andin particular rotational bearings are provided at the said laterallyspaced portion of the roller housing to facilitate sliding engagement ofthe mounting plate thereon under impulse of the eccentrically mountedroller.

[0028] The mounting plate is preferably detachable. Provision of adetachable mounting plate is of particular advantage in embodiments ofthe invention where the roller or rollers are configured to comprise atleast part of the engagement means for a wheeled carriage. Using themounting plate then provides an alternative means of mounting, and inparticular allows the option where the roller(s) are specially adaptedto receiving a wheeled carriage with wheels of a given size orconfiguration of using the device also in conjunction with un-wheeledcarriages or carriages with other wheel arrangements or sizes.

[0029] The or each roller is manufactured from any suitable materialcapable of providing the requisite strength and stiffness for theapplication envisaged. Preferably, the or each roller is of tubularconstruction. Preferably, the or each roller is manufactured from areasonably stiff metallic material, such as tubular steel.

[0030] Alternatively, the or each roller may be fabricated from a stiffplastics material, such as a fibre reinforced composite material, forreduced weight.

[0031] Similarly for reduced weight the or each roller may be hollowrather than solid, and/or may have an open structure in which therolling surface is not a complete cylinder but comprises only surfaceportions suitable for engaging a mounting means or carriage in use.

[0032] The or each roller may be provided with a surface layer, forexample of rubber or plastics material, to provide additional surfaceproperties, for example in relation to improving engagement of thecarriage and/or mounting plate thereon. Similarly, the surface maycomprise additional means to effect and/or improve engagement of thecarriage thereon.

[0033] Additionally or alternatively, the surface of the or each rollermay comprise projections, undulations or other like adaptationsconfigured to impart further oscillation to a carriage mounted thereon(that is oscillation additional to that arising as a consequence of theoverall transverse shape and/or eccentric mounting of the oscillatingroller). In a preferred embodiment, at least one roller is provided withsmall surface projections to impart additional oscillation. In thisembodiment the roller imparts both a larger scale longer periodoscillation attributable to the overall transverse shape and/oreccentric mounting and a smaller scale shorter period oscillationattributable to the uneven surface. This combined effect can bebeneficial, mimicking, for example, the acknowledged effect of rocking apram back and forth over the edge of a carpet.

[0034] The or each roller and/or surface portions thereof are preferablyremovable to provide alternative configurations in which first a smoothroller is provided, producing a single oscillation type, and second anundulating roller is provided, producing the bi-modal oscillation effectas above described. This allows the user to choose the most effective.It may be noted that the former is often more effective for the youngestbabies, and the latter for older infants.

[0035] Any suitable drive means may be used to drive the device, but asimple electric motor is likely to be preferred. The drive means may actdirectly to rotate the driven roller, or may act through a suitabledrive belt or the like. Where an electric motor is used, the devicepreferably further comprises a means to engage the electric motor with asuitable power supply. Typically, this will be the domestic mainssupply. In these circumstances, an electric motor may be driven directlyat mains voltage, but the device preferably further comprises a suitabletransformer to step down the domestic mains supply voltage to apreferred operating voltage, which will be considerably lower forsafety. For example, this will step down the European domestic supplyvoltage of 220V/240V to a lower motor voltage (for example 12V or 24V).

[0036] The drive means has preferably associated therewith a timingmeans, which may be preset by the user to a predetermined time, afterwhich it will switch off the drive means. This further minimises thedegree of the baby's carer's involvement in the operation of the device.

[0037] Optionally the system could also include a sound generator, suchas a tape player, to play suitable soothing sounds during use (music,mother's voice etc). This can also be linked operatively to the timingmeans.

[0038] Additionally, the drive means preferably has associated therewithspeed control means to allow the user to control the speed at which theroller is rotated, and hence the frequency of oscillation.

[0039] The device may further comprise other means to soothe the baby,in particular means which take the form of soothing visual and/or auralstimuli.

[0040] The device may be user actuated, or may provide further means toactuate automatically, for example in response to the baby's crying.

[0041] In accordance with a further aspect of the invention, there isprovided a method of rocking a baby's carriage, comprising the steps oflocating a lower part of a carriage, perambulator, cot or the like inmechanical association with an elongate, generally horizontally mountedroller, wherein the transverse shape of the roller and the position ofthe mounting axis are together such that the roller is capable ofimparting and oscillating motion to the carriage, perambulator, cot orthe like, causing the said roller to rotate by operation of suitabledrive means, thereby imparting an oscillating motion to the lower partof the carriage, perambulator, cot or the like.

[0042] Preferably, the method is used with wheeled carriages, and theroller is adapted to receive a wheel or wheels of such wheeledcarriages. In a preferred embodiment of the method, a plurality ofrollers is provided, and more preferably a pair of rollers comprising aneccentrically mounted roller and a centrally mounted roller is provided,and the first step of the method comprises locating wheel or wheels ofwheeled carriage in position therebetween.

[0043] Further preferred features of the method will be understood byanalogy to the device features above described.

[0044] According to a further aspect of the invention there is provideda kit of parts for a baby rocker comprising a housing for receiving atleast one roller in an eccentric mounting and/or for receiving at leastone roller having an eccentric transverse profile drive means to causethe roller to rotate, at least one roller, and preferably a plurality ofrollers having different surfaces and/or a plurality of interchangeableroller surfaces, and optionally further comprising a mounting plate toseat over the oscillating roller.

[0045] The invention will now be described by way of example only withreference to the accompanying drawings in which:

[0046]FIG. 1 is a plan view of a baby rocker in accordance with thepresent invention;

[0047]FIG. 2 is a side elevation of the same;

[0048]FIG. 3 is a schematic transverse section of the device of FIG. 1further incorporating a receiving plate;

[0049]FIG. 4 is a transverse section of a preferred embodiment of rollerfor use with the device of FIGS. 1 to 3;

[0050]FIG. 5 is an exploded perspective view of an alternativeembodiment of a baby rocker in accordance with the present invention;

[0051]FIG. 6 is an exploded perspective view of a further alternativeembodiment of a baby rocker in accordance with the present invention.

[0052] Referring first to FIGS. 1 and 2, a pair of elongate rollers 1, 2are shown mounted in parallel in a roller housing (14). The pair ofrollers comprises a concentrically mounted idler roller (1) and aneccentrically mounted driven roller (2), both rollers mounted throughbearings (8).

[0053] The eccentrically mounted driven roller (2) is powered by a drivemeans in the form of a 12 volt motor (9) which is adapted to receiveregular mains power, from a power supply (3). A transformer (4) stepsthis down to 12 volts, and power is then supplied to the motor by powercable (17) through cable conduits (10). Associated with the power sourceare a timer switch (5), a two speed toggle-switch to control rotationalspeed (7), and a fuse (6) of a rating suitably selected to preventengine burn-out problems if the device is excessively loaded.

[0054] The whole device is contained within a housing (14) comprising abase plate (15) designed to engage with and given stable support uponthe ground, and mounting portions (16) which hold the bearings andcomponents associated with the power supply and drive means.

[0055] Operation of the device is illustrated schematically in FIG. 3.In FIG. 3, the device is shown in use with an optional mounting plate(13) engaged upon the rollers. It will be understood from the text abovethat this mounting plate may be dispensed with, and, for example, thewheels of a pram or the like engaged directly upon and between therollers.

[0056]FIG. 3 illustrates the position of the concentric roller (1),eccentric roller (2), and optional mounting plate (13), both in aninitial position (solid line) and in a series of further positions asthe eccentric roller is caused to rotate by the motor (broken lines).

[0057] As the eccentric roller rotates, it imparts a rocking motionincorporating the significant up and down element to the mounting plate(13) in the embodiment illustrated; or alternatively directly to thecarriage and in particular to wheels of the carriage. In this way, arocking motion may be applied to the carriage to soothe the baby inside.

[0058] The rollers are of tubular construction, and in this embodimentare of tubular steel. A plastic surface layer may be applied to improveadhesion with the pram wheels or the like. However, alternativematerials both for the body of the roller and for any surface treatmentswill readily suggest themselves.

[0059] A particularly preferred embodiment of roller is shown incross-section in FIG. 4. In this case, apertures are provided within thetube for receiving detachable rubber stubs (12). Once in place, therubber stubs (12) project out from the roller surface. The rubber stubsmay be arrayed along the length of the roller, or may take the form ofan elongate ridge along the roller surface. In either case, the purposeof the stud is to impart further oscillation to a carriage mountedthereon, in addition to the oscillation already imparted as a result ofthe eccentric mounting of the roller (2). The effectiveness of this typeof oscillation will be well understood by analogy to the recognisedenhanced effect produced by rocking a pram backwards and forwards over asurface irregularity, such as a carpet edge.

[0060] Referring to FIG. 5, an alternative embodiment of the baby rockeris shown in which only a single, eccentrically mounted roller isprovided in conjunction with a mounting plate to impart a rocking motionto a carriage or the like.

[0061] An eccentrically mounted driven roller (22) is mounted in use ina roller housing (24) by means of off-centred mounting lugs (23) whichare received in apertures (25) in side walls (26) of the housing (24).The eccentrically mounted driven roller (22) is powered by a suitabledrive means (not shown) which may be in the form of the drive means inthe previous embodiment or any other suitable form.

[0062] The rocking motion is imparted to a carriage or the like mountedupon a mounting plate (27) which is in use received over theeccentrically mounted roller by means of the hollow mounting section(28). The mounting plate (27) further includes a flat carriage supportarea (29) with a suitable non slip surface or the like, and raisedportion (30) rearward of the flat portion (29) to safely retain wheelsor legs of a carriage or the like in position in use and prevent themsliding out as the mounting plate (27) oscillates under action of theeccentrically driven roller (22).

[0063]FIG. 6 is an alternative embodiment of baby rocker in which, inlike manner to FIG. 5, only a single eccentrically mounted roller isprovided in conjunction with a mounting plate. However, in thisembodiment, an alternative arrangement of roller is shown.

[0064] An eccentrically mounted driven roller (32) is mounted in use ina roller housing (34) by means of mounting projections (33) which arereceived in apertures (35) in side walls (36) of the housing (34).

[0065] The roller in this instance comprises, in addition to themounting projections (33), a central structural cylindrical portion (37)and a pair of annular bearings (38) positioned therearound which in useprovide the surfaces in rolling engagement with a mounting plate (41).The combination of mounting projections (33), structural member (37) andbearings (38) thus comprises an eccentric roller arrangement equivalentto the roller (22) in FIG. 5.

[0066] The roller arrangement is driven by the electric motor (39). Thebearings (38) are received in a hollow mounting section (42) of themounting plate (41) and in part an orbital motion thereto. The mountingplate (41) has a flat carriage support area (44) in like manner to themounting plate of FIG. 5 and on which the wheels or legs of a carriageor the like can be safely retained as the mounting plate oscillatesunder action of the roller arrangement. A rearward part (43) of themounting plate slidingly engages over a rear edge of the housing. Inaccordance with the arrangement, action of the roller arrangementimparts an orbital motion to the mounting plate (41), and in particularthe carriage support area (44), and thereby to the wheels or legs of acarriage or the like placed thereupon.

[0067] An optional wheel support clip (47) is provided, particularly toaccommodate larger-wheeled prams and the like, which might otherwise notrest so stably on the area (44). A base (48) of the wheel supportslidingly engages with a ridged engaging portion (46) on the mountingsection (42) and rearward extension (43) of the mounting plate (41). Thewheel rests in the arcuate upper part of the clip. Different clips maybe provided to accommodate differently-sized wheels.

1. A rocking device comprising means for receiving a lower part of acarriage, perambulator, cot bed or the like, an oscillation means forimparting an oscillating motion thereto comprising an elongate rollermounted about a generally longitudinal axis, and drive means associatedtherewith to cause the roller to rotate, the roller being mounted aboutan eccentric axis such that the roller imparts an orbital oscillatingmotion to the carriage in mechanical engagement therewith in use.
 2. Arocking device in accordance with claim 1 wherein the oscillating rolleris generally cylindrical.
 3. A rocking device in accordance with claim 2wherein the oscillating roller comprises a solid or hollow elongatecylinder having an offset axial mounting.
 4. A rocking device inaccordance with claim 2 wherein the oscillating roller comprises anelongate central structural portion, offset mounted, and provided withone or more annular rolling surface portions whose radially externalsurfaces comprise rolling surfaces together constituting a virtualcylindrical rolling surface.
 5. A rocking device in accordance withclaim any preceding claim further comprising receiving means having areceiving surface for receiving a lower part of a carriage and anengagement surface seating upon the oscillating roller which serves toimpart an orbital oscillating motion thereto transmitted by thereceiving means to a carriage received thereon.
 6. A rocking device inaccordance with claim 5 wherein the receiving means comprises a mountingplate having a mounting portion which seats over the oscillating rollerand a receiving portion for receiving the lower part of the saidcarriage.
 7. A rocking device in accordance with claim 6 furthercomprising a second centrally mounted roller generally parallel to theoscillating roller and a mounting plate comprising a mounting portionwhich seats over the rollers and a receiving portion for receiving thelower part of the said carriage.
 8. A rocking device in accordance withclaim 7 comprising an eccentrically mounted roller and a centrallymounted roller, both generally circular-cylindrical, wherein themounting plate comprises a first mounting portion configured to engagethe eccentrically mounted roller, a second mounted portion configured toengage the centrally mounted roller, and a receiving portiontherebetween.
 9. A rocking device in accordance with claim 6 comprisinga generally circular-cylindrical eccentrically mounted roller, within asuitable roller housing, the mounting plate comprises a first mountingportion configured to engage the eccentrically mounted roller, a secondmounted portion configured to engage a laterally spaced portion of theroller housing and a receiving portion therebetween.
 10. A rockingdevice in accordance with claim 5 wherein bearing surfaces and inparticular rotational bearings are provided at the said laterally spacedportion of the roller housing to facilitate sliding engagement of themounting plate thereon under impulse of the eccentrically mountedroller.
 11. A rocking device in accordance with any preceding claimwherein the surface of the or each roller comprises projections,undulations or other like adaptations configures to impart furtheroscillation to a carriage mounted thereon.
 12. A rocking device inaccordance with any preceding claim wherein the drive means hasassociated therewith a timing means which may be pre-set by the user toa pre-determined time after which it will switch off the drive means.13. A rocking device in accordance with any preceding claim wherein thedrive means has associated therewith speed control means to allow theuser to control the speed at which the roller is rotated, and hence thefrequency of oscillation.
 14. A method of rocking an object such as acarriage, perambulator, cot bed or the like, comprising the steps oflocating a lower part of the object in mechanical association with anelongate, generally horizontally mounted roller, mounting the rollerabout an eccentric axis, causing the roller to rotate by operation ofsuitable drive means, thereby imparting an orbital oscillating motion tothe lower part of the object.